The objective of this research program is to discover the biochemical mechanisms of sperm-egg interaction in animals. The sea urchin is the only animal producing large enough quantities of sperm and eggs to make this possible. We are working with a new method we have developed to isolate the sperm plasma membrane. The membrane contains three proteins we wish to isolate and assign functions to: The 84K protein which we have shown to be involved in the acrosome reaction triggering mechanism, the 110 and 115K doublet which represents 50% of the total sperm membrane protein and may be a Ca ions sequestering ATPase similar to that from SR. We will also determine if proteins and phospholipids of the sperm membranes are phosphorylated and methylated during the acrosome reaction and the binding of sperm to the egg. We have discovered an inhibitor of the acrosome reaction in the seminal plasma bathing the sperm during storage in the testes. This inhibitor is species specific, is heat sensitive, dialysable and less than 1500 mole.wt. We will attempt to isolate and characterize the inhibitor and study its mode of action on the sperm membrane. We will continue to study the regulation of internal cAMP by external CA ions in abalone sperm. This will also include studying the involvement of calmodulin and diesterase inhibitors on Ca ions transport into the sperm. We will characterize and determine the function of the beta-1,3-glucanase we have just purified from eggs. We will localize the enzyme in the egg by immunoperoxidase and also isolate the natural substrate for the enzyme. We are working on the complete biochemical characterization of egg cortical granules which we can isolate as pure granules in an attempt to learn more about the Ca ions-mediated disruption of the granules. The knowledge we will acquire from these studies will someday be applied to the development of novel methods of non-hormonal contraception in higher organisms.